To understand the download, you must understand what the file actually is. Samsung TVs do not run on a generic BIOS. They run on Tizen, which requires a specific hardware abstraction layer (HAL) for every model series.
Here is the official, safe way to get the firmware for your Samsung TV. firmware tv samsung download
If your TV isn't connected to Wi-Fi, or if the auto-update keeps failing, use the USB method. To understand the download, you must understand what